Fig. 1From: MR-guided proton therapy: a review and a previewModel of the magnetic interaction between an MRI and PBS assembly when delivering a scanning pattern down the bore of the MRI. Example of a scanned pencil beam with the MRI scanner turned off (a) and on (b). c Scanning magnet (SM) settings and MFH over the scanning pattern shown in (d). e Changes to the scanning pattern due to the presence of the magnetic field from the MRI scannerBack to article page